The present invention refers to a splicing device for laminar webs, designed for the automatic joining of webs that are supplied continuously to application processes.
In the processes involving the feeding of laminar webs, for example in the formation of corrugated board or in other applications of a similar nature, in order to ensure the continuity of the feed without having to interrupt the process, at least two reels containing the material to be supplied are provided, so that whilst the material is supplied by one of the reels, the other reel is ready in stand-by, so that when the reel currently providing the supply runs out, the supply is then provided by the reel that is in stand-by.
In order not to have to halt the process during the changeover of the supply reels, splicing mechanisms have been developed, in order to perform an automatic splicing between the end of the spent reel and the leading edge of the reel in stand-by, such as, for example, the solutions covered by Spanish Patent 484,893 and Patent 200002234, amongst others, by the same holder of the present invention.
Said splicing mechanisms perform the join by adhesion between the end of the web of the reel that is running out and the leading edge of the web of the reel that is in stand-by, cutting any excess off the finished web, in a manner whereby as of that moment the web continues to be supplied from the second reel, whilst in the place of the spent reel another reel can be mounted and made ready in stand-by to be subsequently joined, in the same way, to the infeed web when the infeed reel runs out. Accordingly, the aforementioned splicing devices consist of two reel-carriers, upon which respective structures are mounted in a travelling carriage, through one of which the infeed web passes, whilst in the other preparation is made of the web that is to remain in stand-by, with the aforementioned structures provided with devices that allow for the sticking and cutting of the two webs for the continuance of the feed when the supply reel runs out.
Existing splicing devices nevertheless feature deficiencies in terms of the precision and accuracy of their operation, allowing for the possibility of a faulty join in the webs that may affect the application process and/or the result of this application.
In that sense, in accordance with the present invention, a splicing device is proposed that is fitted with means of operation and structural features that permit the splicing of the webs to be effected both precisely and accurately, removing any possible defect that may compromise the application process or the condition of the corresponding end product.
The splicing device that is covered by this invention consists of respective preparation heads above the respective reel-carriers and between them a moving head that may be displaced between the positions of the aforementioned preparation heads, with each of these preparation heads including a fixed roller, upon whose shaft a tilting system is fitted and operated by a pneumatic cylinder, which comprises at one end a preparation section and, at the other end, a roller sheathed in an elastic material, with regard to whose shaft an attachment section is fitted, which may tilt operated by a pneumatic cylinder.
The preparation cylinder is fitted with a vacuum system for holding the end of the web to be prepared, furthermore incorporating a cutting mechanism for transversally cutting off said leading edge of the web to be prepared.
The moving head consists of two rollers fitted with a pneumatic brake and radially driven by respective pneumatic cylinders, as well as by respective cutting systems, also operated by pneumatic actuators, and a bar that incorporates a vacuum holding system.
The splicing device is integrated with a tension unit on the web being fed, consisting of a hollow drive roller with a vacuum system for holding the web to it; with there also being a group of moving rollers above the splicing device unit which constitute a return loop of variable length through which the infeed web passes.
This therefore provides a unit that allows for the web to be fed to the corresponding application from a supply reel placed on one of the reel-carriers, while the web on the other reel that is to remain in stand-by is being prepared, so that when the infeed reel runs out, automatically and by means of a functional actuation procedure between the moving head and the preparation head that corresponds to the web in stand-by, the web in stand-by and that being fed are joined automatically and the latter is cut off.
The process is undertaken in conjunction with the operation of the tension unit on the web being supplied and of the return loop of variable length, in a manner whereby the splicing between the two webs is effected quickly and with the utmost accuracy, maintaining the continuity of the supply of web to the application process.